1. Field of the Invention
The present invention relates in general to medical instrumentation, and more particularly to intraluminal devices, and still more particularly to guide wires for intraluminal devices including catheters.
2. Description of the Prior Art
The use of intraluminal catheters for treatment of various medical problems within the body is well known. It is also well known that a variety of problems are encountered as the catheter is steered through the selected lumen to a desired point in the body. The path may be tortuous and the point of interest may be difficult to locate precisely. A continuing series of technical improvements and additions have been made in the catheter field to provide devices and methods which can overcome certain of the difficulties. One such series of improvements has resulted in the now well known use of a thin flexible guide wire which includes a radiopaque tip or distal portion and which can be more easily steered through the lumen and which can be more precisely placed with the use of a fluoroscope to read the location of the tip. A desired catheter can then be slid over the guide wire to reached the desired situs in the body.
U.S. Pat. No. 3,789,841, for example, teaches the use of a guide wire having portions of uniform diameter adjacent to portions of tapered diameter to provide increase flexibility. The teaching includes encasing the distal end of the guide wire in a coiled spring and the remainder of the wire in a Teflon jacket.
U.S. Pat. No. 4,545,390, for example, also teaches the use of a thin guide wire having both uniform and tapered diameter portions and having a helically wound spring encasing a tapered portion at its distal end. In this teaching, at least part of the spring is formed from a material having a high degree of radiopacity for the purpose of fluoroscopic observation.
U.S. Pat. No. 4,884,579, for example, teaches yet another version of the above described thin, flexible guide wire that has a portion encased in a lubricous material such as Teflon to facilitate the passage of a catheter over the wire after it has been situated in the body.
U.S. Pat. No. 5,201,754 teaches the use of varying radiopacity in an angioplasty balloon catheter to better enable its steerage through a body lumen.